Stormwater runoff is characterized by the United States Environmental Protection Agency as one of the greatest remaining sources of water pollution in America. Thus, efforts to implement stormwater quality improvement regulations are accelerating across the United States, compelling municipalities and land developers to maximize the usefulness and effectiveness of stormwater infrastructure as never before.
In urban, suburban, and commercial settings, polluted stormwater, also referred to as wastewater, is often collected in a catch basin, also referred to as a wastewater basin. In its simplest form, a catch basin functions to intercept surface water flows in order to prevent the accumulation of stormwater in an area where flooding could impede traffic or pedestrians, cause property damage, or otherwise present a nuisance. Stormwater collects in the catch basins, and flows through a network of pipes, sewers, and additional catch basins to an outlet point such as a lake, stream, river, ocean, unpopulated area, or similar location where the wastewater may be dispersed without the threat of flood or property damage. However, catch basins are also often the entry point of pollutants from diffuse sources found in stormwater runoff. For example stormwater runoff may contain pollutants such as hydrocarbons (also referred to as “oil”), bacteria, sediment, trash, organic material such as leaves, grass clippings, particulate, soil, detergents, coolants, grease, fertilizer, paint, and feces. As a result, polluted wastewater is often discharged, untreated, directly into lakes, streams, and oceans.
Prior art hoods include cast iron hoods sealably mounted to the walls of catch basins. These systems are based on the principle of differential specific gravity separation. The liquid mixture, which usually is wastewater, flows slowly through an elongated path in a liquid-retaining structure, such as, for example, a catch basin. The matter to be collected is usually oil and floatable debris and other types of surface debris which accumulate on the surface of the wastewater because they have a specific gravity lower than that of water. Alternatively, as the wastewater flows through the catch basin solids carried by the wastewater accumulate on the bottom of the basin. These solids sink to the bottom of the catch basin because they have a specific gravity greater than water. The problem with these catch basins is that debris and trash may collect inside of the outlet pipe and in the interior of the hood. To remove any debris, or to perform maintenance on the outlet pipe, the hood has to be completely removed, unsealing the hood from the wall, to gain access to the interior of the hood and the outlet pipe.
To overcome this problem, and to gain access to the interior of the hood and the outlet pipe, a cast iron hatch was hingedly attached to the wall of the catch basin. The hood could be lifted up to allow access to the interior of the hood. These hoods had many disadvantages. First, the hoods were not sealably mounted to the wall of the catch basin, allowing a significant amount of debris to flow beyond the hood. Second, the hoods were very heavy to lift up as they had to be made of cast iron.
To overcome the problems with previous hoods, hoods composed of a material other than cast iron were designed with a port hole-like opening at the top. In reference to FIG. 1, a known outlet hood 10 with this design is shown. The hood 10 is installed to the wall 20 of a catch basin over an outlet pipe 30 in the wall 20 of the catch basin. The outlet pipe 30 is shown with hidden lines and its distal end appears to protrude slightly from the wall 20 of the catch basin.
The hood 10 further includes a porthole 40 to allow access to the interior of the hood. A maintenance worker must climb down into the catch basin and open the porthole by manually unscrewing a cover, revealing an opening into the hood 10. The maintenance worker then, either manually or with a suction mechanism, can remove any debris that may have collected inside of the hood or perform maintenance and service on the outlet pipe.
A disadvantage of this hood is that a maintenance worker needs to enter the catch basin in order to remove the cover of the porthole and remove any debris that may have entered the hood. This requires the maintenance worker to wear protective gear to protect the worker from the water-born toxins and other pollutants in the catch basin. Having to wear protective gear, and the need to enter the catch basin, increases the amount of time needed to access the inside of the hood, which adds a significant amount of time to perform maintenance or service on multiple catch basins. Additionally, having to enter the catch basin exposes the maintenance worker to harmful gases, material, and debris. This can affect the health of the worker, and increase the health care costs associated with this profession.
Another disadvantage is the hood requires a mechanical mechanism to seal the porthole. Mechanisms such as threads and cam-locks, which are used in this type of hood, are more susceptible to failure in that they may be difficult to open and close even if the person is in the catch basin. In order to have an effective seal to prevent surface debris, such as oil, from passing through the port hole, the prior art covers needed screwed thread connections that need manual tightening to be effective. This requires substantial time and effort by the maintenance worker. Water, sediment, and harsh materials may impact the performance of a traditional mechanism used to seal the porthole, which may prevent access the porthole as the cover may be stuck.
Another disadvantage of this hood is that it can only be installed in catch basins with enough room for a maintenance worker to enter the catch basin. The catch basin must be sufficiently large for the hood plus a maintenance worker, and requires enough height clearance for the cover of the porthole to be completely removed. The confined space entry in these smaller catch basins can create dangerous conditions for maintenance workers who need to enter the basin to perform maintenance activity. These catch basins cannot be installed in small catch basins, such as basins sized at 18 inches.
What is desired therefore is an apparatus for reducing the flow of pollutants such as hydrocarbons, sediment, soil, trash, and floatables into the outlet of a catch basin. Another desire is for an apparatus that does not require a person to enter the catch basin in order to clean out any debris that may have entered the hood or access the opening. Another desire of this apparatus is to limit the number of components to prevent the failure of the apparatus. Another desire is an apparatus that is modular to allow the hood to be easily installed in catch basins that may only have a small opening in the ground from which water flows into. Another desire is an apparatus that can be used in small catch basins that are not large enough for a person to enter. It is also desirable to have a partially liftable and flexible hatch that would permit access to the outlet pipe to perform things such as pipeline surveillance and root scouring.